Download the file and save it to Desktop. Open an "admin" Command Prompt
Note: You must copy and paste (into Notepad) the text on the Doug Knox page then save it as xp_cd_dvd_fix.vbs
then run the .vbs file by typing the following at the console window:

Reboot the pc or "scan for hardware changes". Your drive(s) should now be visible in My Computer and work properly.
If the drive still fails to work properly after performing any of these fixes, it most likely will need to be replaced.